1Fig. E.15HOX genes: Comprehensive example2Fig. E.163Fig. E.174Lecture 22: Cell-Cycle Regulation and theGenetics of Cancer IRead 617-626Fig. 18.2-18.135The normal cell divisionThe cell cycle hasfour phases:G1, S G2, and MFig. 18.26Isolation of temperature-sensitivemutants in yeast• Mutants grow normally atpermissive temperature• Mutants loses genefunction at restrictivetemperature• Thousands of cell cyclemutants have beenidentifiedFig. 18.37A cell-cycle mutant in yeast• (a) growth at permissivetemperature displays buds ofall sizes• (b) growth at restrictivetemperature shows cells havefinished first cell cycle andarrested in the secondFig. 18.4870 cell-cycle genes identified throughtemperature-sensitive mutation screens9Normal gene product must be produced ata particular stage in cell cycleFig. 18.610A double mutant reveals which mutationis epistatic to whichFig. 18.511Cyclin-dependent kinases (CDK) control thecell cycle by phosphorylating other proteinsFig. 18.7a12Nuclear lamins are one of the substrates of CDKFig. 18.7b13Human CDKs and cyclins can function inyeast in place of native proteinsFig. 18.814Three cell cycle check points ensure genomic stabilityG1 to S (start) check pointsG2 to M check pointsMetaphase-anaphase check points15CDKs mediate the transition from the G1-to-S phase in human cellsFig. 18.916-members of Li-Fraumeni cancer-prone families wereshown to carry germ-line p53 mutations.-mice that are homozygous null for p53 are highlypredisposed to tumors.p53: an anti-oncogenic protein17Fig. 18.11 ap5318Over 50% cancer cells contain mutations in p53Fig. 18.11 c,d19G2-to-M check pointsFig. 18.1020G2-to-M check pointsFig. 18.12a21Metaphase to anaphase checkpointFig.
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